Steering wheel

ABSTRACT

The present invention provides a steering wheel. Among respective hooks of a module, the hooks being adapted to engage with wires which are disposed in respective opening portions of a steering wheel main body, an adjustment rib which is provided so as to be protrusive to an outer circumferential face of one side hook comes into contact with an inside face of one side opening portion, and restrains a position of such one side hook in such one side opening portion. An adjustment pin which is protrusively provided at a position different from that of the adjustment rib on the outer circumferential face of such one side hook elastically comes into contact with the inside face of such one side opening portion by the adjustment rib coming into contact with the inside face of such one side opening portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of Japanese Patent Application Nos.2014-055470 filed on Mar. 18 2014 and 2014-266284 filed on Dec. 26,2014. The contents of the preceding applications are incorporated hereinby reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a steering wheel provided with aplurality of engagement members which are respectively engaged withhooks which are inserted through a plurality of hole portions to therebysupport a module with respect to a steering wheel main body.

2. Description of the Related Art

Conventionally, a steering wheel of a motor vehicle has been known thatthere is provided the one that is configured by mounting a module suchas an airbag device provided with: an airbag folded at a boss portion (aboss cored metal) which is a supporting portion constituting a steeringwheel main body; an inflator adapted to supply a gas to the airbag; abase plate to which the airbags and the inflator are mounted; and acover body which is coupled with a base plate and which is adapted tocover the airbag and the inflator.

In addition, as such an airbag device, it has been known that there isemployed a construction in which, with respect to snap lock springs(wires) which are U-shaped engagement members respectively disposed atthree parts, both side parts and a lower part of through holes providedin the base plate of a case body of the module, a plurality of hookswhich are engagement portions provided at the boss portion of thesteering wheel main body are respectively pushed into the through holesand then are hooked on the snap lock springs to thereby mount the moduleto the boss portion with just one touch of a finger.

In a case where such a module is thus mounted to the boss portion withjust one touch of a finger, although the module is positioned in a frontface to rear face direction with respect to the boss portion by way ofengagement between the hooks and the snap lock springs, positioning inthe vertical and transverse direction cannot be achieved by way of theengagement therebetween; and therefore, a positioning pin (a locatingpin) for the purpose of positioning in these vertical and transversedirections is provided separately from a respective one of the hooks(for example, reference should be made to Japanese Unexamined PatentApplication Publication No. 2011-148478).

In recent years, downsizing of an airbag device for steering wheel hasmade a remarkable progress, and it has been not easy to sufficientlyallocate a space for providing a positioning pin.

SUMMARY OF THE INVENTION

The present invention has been made in view of such a circumstance, andit is an object of the present invention to provide a steering wheelwhich is capable of reliably positioning a module with respect to asteering wheel main body while coping with downsizing of the module.

A steering wheel according to a first aspect of the present invention isprovided, and comprises: a steering wheel main body; a module; aplurality of hole portions which are provided at either one of thesteering wheel main body and the module; a plurality of hooks which areprovided at another of the steering wheel main body and the module andwhich can be respectively inserted into the hole portions; and aplurality of engagement members which are disposed at the respectivehole portions, which are biased in a predetermined direction crossing aninsertion direction of the hooks into the hole portions, and which areengaged with the hooks that are inserted into the hole portions so as toretain the hooks to thereby support the module on the steering wheel,wherein the hook that is one of the plurality of hooks comprises: apositioning reference portion which is protrusively provided on anoutside face and which comes into contact with an inside face of one ofthe hole portions so as to restrain a position of one of the hooks atthe one hole portion; and a plurality of adjustment portions which isprotrusively provided on an outside face at a position different fromthe positioning reference portion and which elastically comes intocontact with the inside face of the one hole portion by the positioningreference portion coming into contact with the inside face of one of thehole portions.

A steering wheel according to a second aspect of the present inventionis provided in such a manner that a sum of biasing loads with respect tothe plurality of hooks of the plurality of engagement members issubstantially 0.

A steering wheel according to a third aspect of the present invention isprovided in such a manner that other remaining hooks except one of theplurality of hooks comprise a plurality of adjustment portions which areprotrusively provided on the outside face and which elastically comeinto contact with the inside faces of other remaining hole portions bythe positioning reference portion of one of the hooks coming intocontact with the inside face of one hole portion.

A steering wheel according to a fourth aspect of the present invention,further comprising: a locking portion which is provided between eitherof the pair of the hole portions and the pair of the hooks in either oneof the steering wheel main body and the module; and a locking receivingportion which is provided in another of the steering wheel main body andthe module and which is adapted to engagingly lock the locking portionin the insertion direction of the hooks into the hole portions.

In so far as the steering wheel according to the first aspect of thepresent invention is concerned, among the plurality of hooks that areinserted into the hole portions and that are retained so as to beengaged with the engagement members, the positioning reference portionthat is protrusively provided on the outside face of one hook comes intocontact with the inside face of one hole portion. In this manner, theposition of one hook at such one hole portion is restrained, and theplurality of adjustment portions that are protrusively provided atpositions which are different from that of the positioning referenceportion on the outside face of such one hook elastically comes intocontact with the inside face of one hole portion by coming into contactwith the inside face of one hole portion of the positioning referenceportion; and therefore, it becomes possible to integrate respectivefunctions of supporting and positioning the module with each other withrespect to the steering wheel main body, and it becomes possible toreliably position the module and the steering wheel main body whilecoping with downsizing of the module.

In so far as the steering wheel according to the second aspect of thepresent invention is concerned, the sum of biasing loads of theplurality of engagement members with respect to the plurality of hooksis obtained as being substantially 0. In this manner, it becomespossible to more reliably position the module and the steering wheelmain body while coping with downsizing of the module, by way ofadjustment of the biasing loads of the engagement members.

In so far as the steering wheel according to the third aspect of thepresent invention is concerned, the plurality of adjustment portions areprotrusively provided on the outside faces of other remaining hooksexcept one of the plurality of hooks, and these adjustment portionselastically come into contact with the inside faces of other remaininghole portions by coming into contact with the inside face of one holeportion of the positioning reference portion of one hook. In thismanner, it becomes possible to reliably whirl-stop the module withrespect to the steering wheel main body, and it becomes possible toreliably position the module and the steering wheel main body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (a) is a plan view showing a state in which a module of asteering wheel according to the present invention is mounted to asteering wheel main body from a rear side (a first embodiment);

FIG. 1 (b) is a sectional view showing a state of insertion of one hookinto an opening portion;

FIG. 1 (c) is a sectional view showing a state of insertion of anotherhook of one side into an opening portion; FIG. 1 (d) is a sectional viewshowing a state of insertion of still another hook of another side intoan opening portion;

FIG. 2 (a) is a perspective view showing a part of one hook; FIG. 2 (b)is a perspective view showing a part of another hook; FIG. 3 (a) is aplan view showing a natural state of an engagement member of the samesteering wheel as above;

FIG. 3 (b) is a plan view showing one engagement member in a state inwhich the engagement member is retained on a steering wheel main body ofthe same steering wheel as above;

FIG. 3 (c) is a plan view showing another engagement member in a statein which the engagement member is retained on a steering wheel main bodyof the same steering wheel as above;

FIG. 4 (a) is a perspective view showing a part of a module from a rearside;

FIG. 4 (b) is a perspective view showing a part of the steering wheelmain body from a front side;

FIG. 5 is an exploded perspective view of the module of the samesteering wheel as above;

FIG. 6 is an exploded perspective view of the same steering wheel asabove;

FIG. 7 (a) is a plan view showing the same steering wheel as above;

FIG. 7 (b) is a side view showing the same steering wheel as above;

FIG. 8 is an explanatory view schematically depicting a wiring layout inthe steering wheel according to the present invention (a secondembodiment);

FIG. 9 is an explanatory view schematically depicting a wiring layout inthe steering wheel according to the present invention (a thirdembodiment);

FIG. 10 (a) is a plan view showing a part of the module of the steeringwheel according to the present invention (a fourth embodiment);

FIG. 10 (b) is a plan view showing a part of the steering wheel mainbody;

FIG. 11 is an exploded perspective view of the steering wheel main bodyand the module of the same steering wheel as above;

FIG. 12 is a perspective view showing a state in which a part of themodule of the same steering wheel as above is mounted to the steeringwheel main body;

FIG. 13 (a) is a plan view showing a state of engagement between a holeportion and a hook;

FIG. 13 (b) is a sectional view of FIG. 13 (a);

FIG. 13 (c) is a side view showing a state of engagingly locking betweena locking portion and a locking receiving portion;

FIG. 14 is an exploded perspective view of the same steering wheel asabove; and

FIG. 15 is a plan view showing the same steering wheel as above.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Hereinafter, a steering wheel according to a first embodiment of thepresent invention will be described with reference to the accompanyingdrawings.

In FIG. 7 (a), reference numeral 10 designates a steering wheel servingas a steering wheel, and the steering wheel 10 is disposed on a frontside from an occupant at a driver's seat of a motor vehicle, and iscomposed of: a module 11; a steering wheel main body 12 serving as asteering wheel main body in a case where the module 11 is mounted to theoccupant's side; a cover body (a body cover) 13 serving as a coveringmember which is mounted to the counter-occupant side of the steeringwheel main body 12; a finisher (a garnish) 14 serving as a decorationmember which is mounted to the occupant's side of the steering wheelmain body 12; and operational switching devices 15, 15 of an audiodevice or the like, in a motor vehicle, although not shown, for example.

It is to be noted that the steering wheel 10 is generally mounted to asteering shaft serving as a steering device, although not shown, thesteering device being provided in a state in which the device isinclined at an angle θ1 with respect to a horizontal direction (aperpendicular direction) (FIG. 7 (b)), and however, hereinafter, adescription will be given on the assumption that: the side of the module11 is defined as an occupant's side, a front side, or a rear side; thesteering wheel side is defined as a vehicle body side, a rear side, or afront side; a forward and backward direction taken along the steeringshaft is defined as an axial side; and directions such as the forwardand backward direction and a vertical direction are defined withreference to a forward direction of a vehicle body provided with thesteering wheel 10.

The module 11 is obtained as an airbag device (an airbag module)provided with: a case 24 provided with a base plate 21 which is amounting member serving as a housing body and an airbag cover 22 servingas a covering body, the case being adapted to house a folded airbag 23;an inflator 25 which is disposed in the case 24; and a retainer 26 orthe like (FIG. 5).

The base plate 21 is also referred to as a back plate or a back holderor the like; the base plate is compatible with a horn plate of a hornmechanism, and the base plate is integrally injection-molded with asynthetic resin, for example. In addition, the base plate 21 is providedwith: a board portion 31 which is a mounting surface portion serving asa case main body; and a peripheral wall portion 32 which is erected on afront side all over the peripheral edge part on a surface side of theboard portion 31 (FIG. 4 (a) and FIG. 5).

In the board portion 31, an inflator mounting hole 34 formed in theshape of a circular hole are opened in a substantially center part, andfour mounting holes 35 are respectively opened so as to surround theinflator mounting holes 34. In addition, in the board portion 31, aplurality of columnar hooks 37 adapted to retractably mount the module11 to a steering wheel main body 12 are protrusively provided on a rearside. Further, to the board portion 31, an electrically conducting plate39 which is electrically conductive and which is adapted to set amovable contact point 38 is integrally mounted.

The hooks 37 are adapted to removably engagingly lock the module 11 andthe steering wheel main body 12 and to guide the module 11 along thefront face to rear face direction with respect to the steering wheelmain body 12. These hooks 37 each are integrally provided with: acolumnar receptacle portion 42 which is provided so as to be protrusivefrom the substrate 31 and which forms a proximal end side; a columnarhook main body portion 43 which is smaller in diametrical dimension thanthe receptacle portion 42 and which is protrusively provided so as to becoaxial to the receptacle portion 42; and a conical insertion portion 44which is provided so as to be coaxial to a tip end part of the hook mainbody portion 43. In addition, these hooks 37 are such that the hook mainbody portion 43 and the insertion portion 44 are inserted into openingportions 47 serving as hole portions of the steering wheel main body 12,which will be described later, and are elastically engagingly lockedwith and retained by wires 48 serving as an engagement membersrespectively mounted to these opening portions 47. In the embodiment, inthese hooks 37, there are set a pair of hooks 37 a, 37 b which are firsthooks (one side and another side of hooks) positioned at both upper sideparts and a lower hook 37 c which is a second hook positioned at a lowercenter part.

The receptacle portion 42 is adapted to retain one end part (a rear endpart) of a horn spring 51 which is a coil spring adapted to bias themodule 11 to a rear side (the occupant's side) with respect to thesteering wheel main body 12, and a plurality of engagingly locking clawportions 52 for engagingly locking the horn spring 51 are protrusivelyprovided in a radial direction.

In the hook main body portion 43, another end part (a front end part) ofthe horn spring 51 is positioned around the side of the receptacleportion 42 that is a proximal end side. Further, the hook main bodyportion 43 is a portion which includes the insertion portion 44 and inwhich a tip end side (a front end side) more significantly than suchanother end part of the horn spring 51 is to be inserted into theopening portion 47 of the steering wheel main body 12. In addition, anouter circumferential face 54 of the hook main body portion 43, which isan outside face of a hook 37 is spaced from an inside face of theopening portion 47; and on the outer circumferential face 54, a pair oflocking recessed portions 55, 55 with which the wire 48 is to beengagingly locked are provided in a recessed manner so as to be adjacentto a proximal end of the insertion portion 44; and further, adjustmentpins 56, 56 serving as adjustment portions are provided so as to facethese locking recessed portions 55, 55 (FIG. 2 (a) and FIG. 2 (b)). Onthe other hand, among the hooks 37, at one side hook 37 a which is ahook, in addition to the locking recessed portions 55, 55 and theadjustment pins 56, 56, an adjustment rib 58 serving as a positioningreference portion is provided along an axial direction at a positionwhich is different from those of the adjustment pins 56, 56, on theouter circumferential face 54 of the hook main body portion 43 (FIG. 2(a)). Therefore, in so far as the hooks 37 are concerned, one side hook37 a serves as a positioning hook, and another side hook 37 b and lowerhook 37 c each serve as a general hook.

The locking recessed portions 55, 55 are provided in a recessed mannerin an axial perpendicular direction with respect to the outercircumferential face 54 of the hook main body portion 43. The lockingrecessed portions 55, 55 of the respective hooks 37 are disposed on bothsides, that is, so as to be linearly symmetrical to each other, withrespect to a direction facing a gravity (a center) of a virtual triangleT connecting center axes of the respective hooks 37 when seen in thefront face to rear face direction. Therefore, the locking recessedportions 55, 55 are positioned on an upper side and another lower sideof the outer circumferential face 54 of the hook main body portion 43,in the respective side hooks 37 a, 37 b, and are positioned at both sideparts of the outer circumferential face 54 of the hook main body portion43, in the lower hook 37 c.

The adjustment pins 56, 56 are adapted to adjust positions of therespective hooks 37 of the respective opening portions 47, and arepositioned at a proximal end side of the hook main body portion 43 moresignificantly than the respective locking recessed portions 55, 55, atip end part of which is positioned in the locking recessed portions 55,55. These adjustment pins 56, 56 each are formed in the shape of atongue which is provided so as to be elastically deformable in an axialperpendicular direction (a radial direction) of the hook main bodyportion 43 of the hook 37, and at a tip end part, there are providedclaw portions 56 a, 56 a, a respective one of which protrudes to theoutside in the axial perpendicular direction more significantly than theouter circumferential face 54 of the hook main body portion 43. Inaddition, in so far as the adjustment pins 56, 56 are concerned, theseclaw portions 56 a, 56 a are respectively capable of elastically cominginto contact (abutment) with the inside faces of the opening portions47.

The adjustment rib 58 serves as a reference which comes into contact(abutment) with the inside face of the opening portion 47 to therebyrestrain the position of one side hook 37 a in the vertical andtransverse directions and then position the module 11 in the verticaland transverse directions with respect to the steering wheel main body12; the adjustment rib protrudes to the axial perpendicular direction(the radial direction) from the outer circumferential face 54 of thehook main body portion 43 of the one side hook 37 a; and the adjustmentrib is formed in a longitudinal shape along the axial perpendiculardirection, that is, along the direction of insertion into the openingportion 48 of the hook 37. Thus, the adjustment rib 58 is adapted tomaintain contact with the inside face of the opening portion 47 in astate in which the module 11 is mounted by operation of a horn device orthe like in the front face to rear face direction with respect to thesteering wheel main body 12. The adjustment rib 58 is set so as to belarger in length in the longitudinal direction than the protrusionquantity in the axial direction from the outer circumferential face 54of the hook main body portion 43. In addition, the position of theadjustment rib 58 is set at a position at which a phantom line L1connecting a center axis of the one side hook 37 a and the gravity (thecenter) of the virtual triangle T (T1) to each other and the outercircumferential face 54 cross each other, in the hook main body portion43 of one side hook 37 a when seen in the front face to rear facedirection. That is, in the one side hook 37 a, the adjustment rib 58 ispositioned so as to be opposite to the adjustment pins 56, 56 withrespect to a phantom line L2 which passes through the center axis andwhich is orthogonal to the phantom line L1.

An insertion portion 44 is formed so as to easily insert the hook 37into the opening portion 47 and so as to be gradually reduced indiameter from a proximal end side which is the side of the hook mainbody portion 43 to a tip end side.

Movable contact points 38 are respectively opposed to fixed contactpoints 63 of a horn mechanism which is disposed on the side of thesteering wheel main body 12 which will be described later, andconstitute a horn switch together with these fixed contact points 63.That is, the movable contact points 38 are respectively positioned atboth side parts and a lower part of the board portion 31 of the baseplate 21.

The electrically conductive plate 39 is formed in the shape of a plateby an electrically conductive metal or the like. It is to be noted thatthe electrically conductive plate 39 may be fixed to the board portion31 by way of claws or the like, or alternatively, when the base plate 21is molded, the plate is insertion-molded, whereby a portion except themovable contact point 38 may be embedded in the board portion 31.

The peripheral wall portion 32 is adapted to surround the airbag 23 inits folded state, and is positioned in a direction taken along theprotrusion direction of the airbag 23. In addition, at the outside ofthe peripheral wall portion 32, a plurality of hook portions 61 and aplurality of locking receiving portions 62 for engagingly locking andretaining the airbag cover 22 are respectively provided.

On the other hand, the airbag cover 22 is integrally molded with asynthetic resin having its insulation property, and is provided with: atop plate portion 64 serving as cover main body which covers a frontside of a part of the steering wheel; and a mounting plate portion 65serving as a mounting wall portion which is provided so as to beprotrusive to a lower side in a rectangular cylinder shape from a frontside which is a rear side of the top plate portion 64.

On a front face which is the rear face of the top plate portion 64, at aposition which is surrounded by the mounting plate portion 65, a tearline which is a tear-off target portion, although not shown, the tearline being formed in the shape of a small groove in a thicknessdimension, is formed in a substantial H-shape in a planar view, forexample, and at the time of inflation of the airbag, the airbag isconfigured to cleave and expand along the tear line by way of anexpansion pressure of the airbag.

The mounting plate portion 65 is positioned outward of the peripheralwall portion 32 of the base plate 21, and is formed along an externalshape of the peripheral wall portion 32. Further, at the mounting plateportion 65, there are respectively provided: insertion opening portions67 which the hook portions 61 of the base plate 21 are respectivelyinserted into and then engaged with; and engagingly locking protrusions,although not shown, which are respectively engaged with the respectivelocking receiving portions 62.

The airbag 23 is formed in the shape of a flat bag by single or aplurality of base cloths, for example, and as is the case with the boardportion 31 of the base plate 21, an inflator mounting hole 71 and fourmounting holes 72 formed in shapes of circular holes are provided so asto surround the inflator mounting hole 71 are formed.

The inflator 25 is provided with: a disk-shaped inflator main bodyportion 74; and a flange portion 75 which is provided so as to beprotrusive from the inflator main body portion 74 to the outercircumferential side. In addition, at the inflator main body portion 74,a gas injection nozzle, although not shown, is provided, and in theflange portion 75, four mounting holes 77 are provided. Further, at abottom part of the inflator main body portion 74, a contact pointportion, although not shown, is provided. To the contact point portion,a wire harness is connected via a connector, although not shown, and viathe wire harness, the inflator 25 is electrically connected to a controldevice.

The retainer 26 is formed in the shape of a ring, and is provided with:a retainer base portion 81 which is formed of a metal plate or the like;and four mounting bolts 82 which are fixed to the retainer base portion81. Also, in the retainer base portion 81, an inflator mounting hole 83formed in the shape of a circular hole is shaped at a center part. Inaddition, the mounting bolts 82 are protrusively provided on the rearside so as to surround the inflator mounting hole 83, and the nuts 84are respectively screwed.

Also, the retainer 26 is inserted into the airbag 23, and the airbag 23is folded in a predetermined shape in a state in which the mountingbolts 82 of the retainer 26 are respectively pulled out from themounting holes 72. Further, the folded airbag 23 is covered with theairbag cover 22, and the insertion opening portion 67 and an engaginglylocking protrusion of the mounting plate portion 65 of the airbag cover22 are pushed against the side of the base plate 21 while the protrusionis positioned at the hook portion 61 and the locking receiving portion62 of the peripheral wall portion 32 of the base plate 21 with themounting bolts 82 of the retainer 26 being inserted into mounting holes35. In this manner, the hook portion 61 is inserted into and thenengagingly locked with the insertion opening portion 67, and theengagingly locking protrusion is inserted into and engagingly lockedwith the locking receiving portion 62 and then the airbag cover 22 andthe base plate 21 are fixed to each other with just one touch of afinger (snap-in).

Further, while the mounting bolts 82 that protrude to the rear side ofthe base plate 21 are inserted into the mounting holes 77, the inflator25 is combined from the rear side of the bas plate 21, and the nuts 84are screwed and tightened with the mounting bolts 82. In this state, aportion on the front side of the inflator main body portion 74 in whichthe gas injection nozzle of the inflator 25 has been provided isinserted into the airbag 23 through the inflator mounting hole 34, andthe module 11 is constructed.

On the other hand, the steering wheel main body 12 is composed of: a rimportion (a ring portion) 87 formed in the shape of a circular ring; aboss portion (a mounting portion) 88 which is provided inside of the rimportion 87; and a plurality of, for example, in the embodiment, threespoke portions 89 which connect these rim portion 87 and the bossportion 88 (FIG. 4 (b) and FIG. 6).

Also, the steering wheel main body 12 is provided with: a metal-basedcored bar 91; a soft covering portion 92 which integrally covers a partof the cored bar 91, and a rear side of the cored bar 91 is covered withthe cover body 13.

The cored bar 91 corresponds to the rim portion 87, the boss portion 88,and the spoke portion 89; the cored bar is provided with: a rim coredbar 95; a boss cored bar 96 serving as a supporting portion; and a spokecored bar 97 serving as a coupling portion; and the cored bar is formedso as to be substantially transversely symmetrical as a whole.

The boss cored bar 96 is also referred to as a boss plate or a hub coreor the like, and is provided with: a boss cored bar main body 102integrally having, at a center part, a cylindrical boss 101 which isengagingly fitted to the steering shaft; coupling cored bars 103respectively adapted to couple the boss cored bar main body 102 and arespective one of spoke cored bars 97; and fixing portions 104 providedat these coupling cored bars 103.

The coupling cored bars 103 are respectively protrusively provided atboth upper side parts and a lower center part of the boss cored bar mainbody 102. That is, at the coupling cored bars 103, a pair of sidecoupling cored bars 103 a, 103 b which are first coupling cored bars(one and another coupling cored bars) positioned at both side parts anda lower coupling cored bar 103 c which is a second coupling cored barposition at a lower part are set.

At the fixing portions 104, there are respectively provided: the openingportion 47; a wire retaining portion 106 serving as an engaginglylocking member retaining portion which retains the wire 48 disposed inthe opening portion 47; and the fixed contact point 63 constituting ahorn switch device. Also, at the fixing portions 104, there arerespectively set: a pair of side fixing portions 104 a, 104 b which arefirst fixing portions (one and another fixing portions) positioned at apair of side coupling cored bars 103 a, 103 b; and a lower fixingportion 104 c which is a second fixing portion positioned at the lowercoupling cored bar 103 c.

The opening portions 47 are provided so as to pass through the bosscored bars 96 in the forward and backward direction which is a thicknessdirection. In so far as the opening portions 47 are concerned, in theside fixing portions 104 a, 104 b, there are formed a pair of sideopening portions 47 a, 47 b which are first opening portions (one andanother opening portions) each formed in the shape of a circular hole,and in the lower fixing portion 104 c, there are formed a lower openingportion 47 a which is a semicircular second opening portion, a lowerside of which is not opposed to the side opening portions 47 a, 47 b isformed in the shape of an arc. That is, in so far as a respective one ofthe opening portions 47 is concerned, an inside face of at least a partthereof is formed along the arc. Also, the side hooks 37 a, 37 b in thehooks 37 are respectively inserted into the side opening portions 47 a,47 b, and a lower hook 37 c in the hooks 37 is inserted into the loweropening portion 47 c.

The wire 48 is also referred to as a “one touch” wire, and is formed ofa wire rod (a piano wire) such as an elastically deformable metal. Inthe embodiment, this wire 48 is provided with: a wire main body 111which is a twisted coil spring and which serves as an engagement membermain body wound in a coil shape; a first arm 112 extending from the wiremain body 111 in a linear shape along a tangential direction; and asecond arm 113 extending in a linear shape along a tangential directionforming an obtuse angle with respect to the first arm 112 from the wiremain body 111; at a tip end side of the first arm 112, locking portions114, 114 respectively adapted to engage with the locking recessedportions 55, 55 of the hooks 37 of the module 11 to thereby engaginglylock the hooks 37 and a removing operation portion 115 for removingoperation, which is continuous between the locking portions 114, 114, isintegrally provided in a V-shape (a U-shape), and a retention targetportion 116 extending in a linear shape on extension of the first arm112 is integrally provided (FIG. 3 (a)). The wire 48 changes an anglewith respect to the first arm 112 and the second arm 113 from a naturalstate (a no-load state) to thereby produce a biasing load so as torestore the angle with respect to the first arm 112 and the second arm113 to the natural state by way of the wire main body 111. In theembodiment, in so far as the wires 48 are concerned, there are set: wirewires 48 a, 48 b which are first wires (one and another wires) mountedto the side opening portions 47 a, 47 b; and a lower wire 48 c which isa second wire mounted to the lower opening portion 47 c which is aposition different from those of the side wires 48 a, 48 b.

Also, a respective one of the wires 48 is pulled in a direction which isopposite to that of the hooks 37 by inserting a tool provided with anL-shaped hook, for example, although not shown, into the removingoperation portion 115, thereby making it possible to disengage thelocking portions 114, 114 and the locking recessed portions 55, 55 ofthe hooks 37 from each other.

The wire retaining portion 106 has: a first retaining portion 117 formedin the shape of circular hole, adapted to retain the wire main body 111;an arm retaining portion 118 which is continuous to the first retainingportion 117, adapted to retain the second arm 113; and a secondretaining portion 119 adapted to the retention target portion 116. Also,by way of the wire retaining portion 106, the side wires 48 a, 48 b areretained so as to bias the module 11 toward the gravity (the center) ofthe virtual triangle T, that is, in a transverse direction and in alower direction; the lower wire 48 c is retained so as to bias themodule 11 toward the gravity (the center) of the virtual triangle T,that is, in an upper direction (a direction which is orthogonal to thatof the steering shaft).

The first retaining portion 117 is provided so as to pass through thefixing portion 104, and the wire main body 111 of the wire 48 is engagedso as to retain the outer circumference of the wire main body 111.

The arm retaining portion 118 is formed in a predetermined directionalong the tangential direction of the first retaining portion 117, andrestrains a turning position of the second arm 113 of the wire 48against biasing.

The second retaining portion 119 is formed in a curved shape along anarc around the first retaining portion 117 at a position which isopposite to those of the first retaining portion 117 and the armretaining portion 118 with respect to the opening portion 47, andrestrains a turning position of the first arm 112 by retaining theretention target portion 116 of the wire 48 at an end part thereofagainst biasing. Therefore, according to a positional relationshipbetween the end part of the second retaining portion 119 and the armretaining portion 118, a relative angle between the first arm 112 andthe second arm 113 of the wire 48 is set, and in the embodiment, thesize of the biasing loads by the wire 48 is set in correspondence with(in proportion to) the size of a collimation angle from the naturalstate of the second arm 113.

Here, a sum of the biasing loads with respect to the hooks 37 by thesewires 48 is obtained as being substantially 0. In the case of theembodiment, the lower wire 48 c does not impart the biasing load in thetransverse direction with respect to the module 11 and thus the biasingloads that are applied in the transverse direction by the side wires 48a, 48 b are set. In so far as the side wires 48 a, 48 b are concerned, acollimation angle θ2 of a respective one of the second arms 113 are setso as to be equal to each other, and these wires are disposed so as tobe transversely symmetrical to each other, that is, at positions whichare symmetrical to each other with respect to the biasing loaddirections by the lower wire 48 c to thereby produce biasing loadstoward directions which are opposite to each other, whereby the biasingloads in the transverse direction are cancelled each other. Therefore, acollimation angle θ3 of the second arm 113 of the lower wire 48 c is setso as to cancel the weight of the module 11 and the biasing loads thatare applied to a lower side by way of the side wires 48 a, 48 b. Thatis, on the assumption that a mass of the module 11 is m and thegravitational acceleration is g, the mass M1 of the module 11 to besupported by the lower wire 48 c is obtained as being M1=m×g×cos θ1. Itis to be noted that a mass M2 of the module 11, which is applied alongthe steering shaft, is cancelled by a biasing load of a horn spring 51.Also, a biasing load F from the side wires 48 a, 48 b to be supported bythe lower wire 48 c is obtained as being F=2×(T1/D)×sin θ4, on theassumption that: an output torque exerted by a respective one of theside wires 48 a, 48 b is defined as T1; a distance from a center of thewire main body 111 of a respective one of the side wires 48 a, 48 b tothe point of action (middle parts of the locking portions 114, 114) isdefined as D; and an angle at which the biasing load from a respectiveone of the side wires 48 a, 49 b with respect to the hook 37 acts on alower side (a direction which is orthogonal to that of the steeringshaft) (an angle in the vertical direction of the first arm 112 whenseen in the front face direction) is defined as θ4. Therefore, an outputtorque T2 required for the lower wire 48 c in order to cancel a sum ofthe weight M1 and the biasing load F (M1+F) is obtained as beingT2=(M1+F)×D and thus the collimation angle θ3 of the second arm 113 ofthe lower wire 48 c is set at θ3=T2/k={(M1+F)×D}/ k, on the assumptionthat a spring constant of the lower wire 48 c is k.

Specifically, in the embodiment, the collimation angle θ2 of arespective one of the second arms 113 of the side wires 48 a, 48 b thatare retained by the wire retaining portion 106 are respectively set to20 degrees (the angle between the first arm 112 and the second arm 113is set to 90 degrees), and the collimation angle θ3 of the second arm113 of the lower wire 48 c that is retained by the wire retainingportion 106 is set to 36 degrees, which is larger than the collimationangle θ2.

The fixed contact points 63 are formed of a member such as a metalhaving its electrical conductivity, and are respectively disposed atboth side parts and a lower part of the boss cored bar 96, the contactpoints protruding to the front side.

A respective one of the spoke cored bars 97 is adapted to radiallycouple the boss cored bar 96 and the rim cored bar 95 to each other, andis bent in a longitudinal wall shape so as to gradually protrude towardthe front face direction from one end part which is continuous to arespective one of the coupling cored bars 103 of the boss cored bar 96to another end part which is continuous to the rim cored bar 95.

Also, in so far as the steering wheel main body 12 is concerned, thecover body 13 is mounted to the steering wheel main body 12 while thecover body is combined and positioned from a rear side. After that, theboss 101 of the steering wheel main body 12 is engagingly fitted to thesteering shaft and then is tightened and fixed with appropriate nuts,although not shown.

To the steering wheel main body 12, the module 11 is mounted with socalled one touch of a finger by pushing it from the front side. That is,when the module 11 is pushed against the steering wheel main body 12from the front side, the wire retaining portions 106 of the wires 48that are positioned in the respective opening portions 47 engage withthe locking recessed portions 55, 55 of the hooks 37, and the module 11engages with the steering wheel main body 12 and then are snap-fittedand supported at three portions, at both sides and the lower side.

In more detail, in the module 11, the hooks 37, a respective one ofwhich protrudes to the most front part, that is, to a position which isopposite to that of the boss cored bar 96, is pushed so as to bepositioned in a respective one of the opening portions 47 that areopened in the base plate 21, the insertion portion 44 of a respectiveone of the hooks 37 serves as a guide and then the hook main bodyportion 43 is inserted into the opening portion 47. At this time, in oneside hook 37 a, the adjustment rib 58 comes into contact with the insideface of a side opening portion 47 a, whereby the module 11 is positionedin the vertical and transverse directions with respect to the steeringwheel main body 12, and in correspondence with this positioning, theclaw portions 56 a, 56 a of the adjustment pins 56, 56 that come intocontact with the inside face of the side opening portion 47 a areelastically deformed to thereby adjust a dimensional difference.Similarly, at the other side hook 37 b and the lower hook 37 c, incorrespondence with the positioning in the vertical and transversedirections by the side hook 37 a and the adjustment rib 58, the clawportions 56 a, 56 b of the respective adjustment pins 56, 56 that comeinto contact with the inside faces of the other side opening portion 47b and the lower opening portion 47 c are elastically deformed to therebyadjust a dimensional difference. That is, one side hook 37 a acts as apositioning reference by the adjustment rib 58, and the other side hook37 a and the lower hook 37 c prevent rotation of the module 11, wherebythe module 11 is positioned with respect to the steering wheel main body12. Further, the insertion portion 44 moves the locking portions 114,114 of the wires 48 that are positioned at a rear side of the openings47 so as to be pressed in a direction which crosses (is orthogonal to) adirection in which the hooks 37 are pushed into the module 11 againstthe biasing load thereof Then the module 11 is sufficiently pushed, andwhen the insertion portion 44 passes through the locking portions 114,114, the wires 48 are restored and deformed and then the lockingportions 114, 114 are engaged with the locking recessed portions 55, 55of the hooks 37 (FIG. 1 (b) to FIG. 1 (d)). As a result, the module 11is positionally restrained in a respective one of the forward andbackward direction, the vertical direction, and the transverse directionso as to be relative to the steering wheel main body 12, and therespective hooks 37 are reliably snap-fitted in the front face directionby the wires 48, and the module 11 is prevented from unintentionallycoming out from the steering wheel main body 12.

Also, in this state, the steering wheel main body 12 is guided along thefront face to rear face direction by way of a respective one of thehooks 37.

In addition, for example, electrical wiring is provided for a contactpoint portion of the inflator 25, whereby the steering wheel 10 that isprovided with the module 11 is constructed while the steering wheel ismounted to the steering shaft.

In the thus constructed steering wheel 10, an occupant at the driver'sseat grips and turns the rim portion 87, whereby operation at the timeof cruising is carried out. Also, the occupant pushes and operates theairbag cover 22 of the module 11 that is compatible with a pushingoperation portion against the biasing load of a respective one of thehorn springs 51, whereby the module 11 is relatively guided to a frontside by way of a respective one of the hooks 37, and if any movablecontact point 38 comes into contact with a fixed contact point 63, ahorn device on the vehicle body side is blown. At this time, in a casewhere the occupant pushes and operates a position biased from a center,such as the top and bottom or the left and right of the airbag cover 22,although the airbag cover 22 moves to the front side in a state in whichthe cover is slightly inclined, the adjustment rib 58 is set onto to onehook (one side hook 37 a) in three hooks 37 (the side hooks 37 a, 37 band the lower hook 37 c) of the module 11; and therefore, such aninclination is not prevented by the adjustment rib 58.

Also, when the module 11 is removed from the steering wheel main body12, a tool provided with a L-shaped hook, for example, although notshown, is inserted into the removing operation portion 115 to therebypull the module in the direction that is opposite to that of the hooks37 and then remove the module from the locking recessed portions 55, 55.In this manner, engagement of the hooks 37 by way of the wires 48 sreleased and then the module 11 can be removed.

On the other hand, in the event of a front face collision of a motorvehicle, a gas is rapidly injected from the inflator 25 into the airbag23 and then the folded housed airbag 23 rapidly inflates. Then, by wayof the inflation pressure of the airbag 23, the airbag cover 22 cleavesalong the tear line and then the protrusion opening of the airbag 23 isformed, and the airbag 23 protrudes from this protrusion opening andthen inflates and expands in front of the occupant to thereby constrainand protect the occupant.

Thus, according to the embodiment, among a plurality of columnar hooks37 which are inserted into the opening portions 47 and which is retainedto be engaged with the wires 48, the adjustment rib 58 that isprotrusively provided on the outer circumferential face 54 of one sidehook 37 a comes into contact with the inside face of one side openingportion 47 a. In this manner, the position of one side hook 37 a in suchone side opening portion 47 a is restrained, and a plurality ofadjustment pins 56 which are protrusively provided at positions, arespective one of which is different from that of the adjustment rib 58of the outer circumferential face 54 of such one side hook 37 a, comeinto contact with the inside face of one side opening portion 47 a tothereby elastically come into contact with the inside face of one sideopening potion 47 a. Then, the respective functions of supporting andpositioning the module 11 with respect to the steering wheel main body12 can be integrated with each other with respect to the respectivehooks 37, the respective opening portions 47, and the respective wires48, and in other words, by the respective hooks 37, the respectiveopening portions 47, and the respective wires 48 that are employed tosupport the module 11 with respect to the steering wheel main body 12,the module 11 can be shared for the purpose of positioning with respectto the steering wheel main body 12, there is no need to allocate a spacein which an additional positioning pin or the like is to be provided,and it becomes possible to reliably position the module 11 with respectto the steering wheel main body 12 while coping with downsizing of themodule 11.

In addition, the biasing loads in the transverse direction of the sidewires 48 a, 48 b are equal to each other, and a biasing load which isapplied to a lower side of the side wires 48 a, 48 b, that is, in adirection facing the lower wire 48 b is equal to a biasing load which isapplied to an upper side by way of the lower wire 48 c, whereby, at aposition at which all the hooks 37 are centered, a sum of the biasingloads of the plurality of wires 48 with respect to the plurality ofhooks 37 is obtained as being substantially 0. In this manner, by way ofadjustment of the biasing loads of these wires 48, it becomes possibleto reliably position the module 11 and the steering wheel main body 12while coping with downsizing of the module 11, and the weight andmanufacturing costs of the module 11 are not adversely affected.Moreover, a biasing load of the wires 48 can be easily changed bychanging a collimation angle of the second arm 113.

Further, except one side hook 37 a, a plurality of adjustment pins 56are protrusively provided on the outer circumferential faces 54 of theother side hook 37 b and the lower hook 37 c, and these adjustment pins56 come into contact with the inside face of one side opening portion 47a of the adjustment rib 58 of one side hook 37 a to thereby elasticallycome into contact with the inside faces of the other side openingportion 47 b and the lower opening portion 47 c. In this manner, itbecomes possible to reliably whirl-stop the module 11 with respect tothe steering wheel main body 12, and it becomes possible to morereliably position the module 11 and the steering wheel main body 12while coping with downsizing of the module 11.

As a result, the layout property becomes advantageous, and downsizing ofthe module 11 or a structural use for a variety of vehicle types becomespossible.

In addition, the adjustment ribs 58 and the adjustment pins 56 of thehooks 37 are taken along the axial direction of the hooks 37 which is adie removing direction at the time of molding of the base plate 21; andtherefore, a molding die of the base plate 21 can be easily moldedwithout any complication.

Second and Third Embodiments

It is to be noted that, in the first embodiment described above, as longas the sum of the biasing loads with respect to the hooks 37 by thewires 48 can be obtained as being substantially 0, that is, the biasingloads by all of the wires 48 can be well balanced, the layout of thewires 48, that is, the positions or shapes of the wire retainingportions 106 and the fixing portions 104 can be arbitrarily set. Forexample, as is the case with a second embodiment shown in FIG. 8, byappropriately changing the biasing load of a respective one of the sidewires 48 a, 48 b (the collimation angle of the second arm 113), thepositions of the side wires 48 a, 48 b may be respectivelyasymmetrically disposed while the respective positions are changed inthe vertical direction and the transverse direction. Also, as is thecase with a third embodiment shown in FIG. 9, in a case where a positionof at least any wire 48, for example, the position of the side wire 48 bis changed along its biasing load direction (coaxially along theresultant force), an asymmetrical layout can be provided without a needto change the biasing load. According to the second and thirdembodiments, it becomes possible to cope with an asymmetrical layout ofthe wires 8 and thus the degree of freedom in design of the steeringwheel 10 (the module 11 and the steering wheel main body 12) isimproved.

In addition, in a respective one of the embodiments described above, thehooks 37 in which an adjustment rib is provided may be the other sidehook 37 b or may be a lower hook 37 c.

Further, the steering wheel 10 can be applied to a construction or thelike provided with two or four spoke portions 89, for example, withoutbeing limited to the construction that is provided with three spokeportions 89.

Furthermore, the wires 48 can be formed in any other arbitrary shapesuch as a U-shape, for example.

Still furthermore, although there has been employed a construction inwhich the hooks 37 are protrusively provided in the module 11 (the baseplate 21) and the opening portions 4 and the wires 48 are disposed inthe steering wheel main body 12 (the boss cored bar 96), there can beemployed a construction in which the opening portions 47 and the wires48 are disposed in the module 11, and the hooks 37 are protrusivelyprovided in the steering wheel main body 12 (the boss cored bar 96).

Yet furthermore, as the module 11, there can be employed a pad bodyadapted to house a shock absorbing body, for example, in place of theairbag device.

INDUSTRIAL APPLICABILITY

The present invention can be preferably employed as a steering wheel ofa motor vehicle, for example.

Fourth Embodiment

Hereinafter, a steering wheel according to a fourth embodiment of thepresent invention will be described with reference to the accompanyingdrawings. According to the present invention, there is provided asteering wheel which can be inexpensively manufactured and which can bedownsized, the steering wheel being capable of easily mounting a module,the steering wheel having an appropriate operability in operation ofbringing a contact point of a horn device into contact with something.As shown in FIG. 10, according to the present invention, openingportions 44 a, 44 a are provided so as to be spaced from each other withrespect to the steering wheel main body 12 a. In a module, hooks 37 a,37 a which can be respectively inserted into the opening portions 44 a,44 a are provided so as to be spaced from each other. Wires 45 a, 45 aare provided in such a manner as to retain the hooks 37 a, 37 a that areinserted into the respective opening portions 44 a, 44 a. In the module,an locking portion 38 a is provided between any of the opening portions44 a, 44 a and the hooks 37 a, 37 a. In the steering wheel main body 12,locking receiving portions 47 a are provided in such a manner as toengagingly lock the locking portions 38 a in a direction of insertion ofthe hooks 37 a, 37 a into the opening portions 44 a, 44 a. At least atpositions of the locking portions 38 a, movable contact points 39 a of ahorn device are provided in the module. In the steering wheel main body12, fixed contact points 48 a of the horn device are provided so as tobe opposed to the movable contact points 39 a.

The present invention relates to a steering wheel provided with aplurality of engagement members which are respectively engaged withhooks which are inserted into a plurality of hole portions so as toretain the hooks to thereby support a module with respect to a steeringwheel main body.

Conventionally, as a steering wheel, that is, a steering wheel of amotor vehicle, there has been a steering wheel configured to mount amodule such as an airbag device provided with: an airbag folded at aboss portion (a boss cored metal) which is a supporting portionconstituting a steering wheel main body; an inflator adapted to supply agas to this airbag; a base plate to which these airbags and inflator aremounted; and a cover body which is coupled with a base plate and whichis adapted to cover the airbag and the inflator.

Also, as such an airbag device, there has been known a construction inwhich, with respect to snap lock springs (wires) which are U-shapedengagement members respectively disposed at three parts, both side partsand a lower part of through holes provided in the base plate of a casebody of the module, a plurality of hooks which are engagement portionsprovided at the boss portion of the steering wheel main body arerespectively pushed into the through holes and then are hooked on thesnap lock springs to thereby mount the module to the boss portion withjust one touch of a finger. In addition, to a respective one of thehooks, a coil spring is mounted, and an airbag device is biased in thefront face to the rear face direction with respect to a boss portion (aboss cored bar). In addition, in opposite to a fixed contact point whichis provided in the boss portion (the boss cored bar), a movable contactpoint is provided in the airbag device and then the airbag device ispushed against biasing of the coil spring, whereby the contact pointscome into contact with each other, and a horn device is blown (forexample, reference should be made to Japanese Patent No. 4797584 andJapanese Patent No. 5240126).

However, in the case of the construction described above, through holes,hooks, and snap lock springs are respectively mounted to three portions,both side parts and a lower part; and therefore, the number of partsincreases, inexpensive manufacturing is not easy, and it takes long toassemble the airbag device. In addition, in the case where these throughholes, hooks, and snap lock springs respectively are disposed at everytwo portions or the like, operability for operating the horn device isnot appropriate.

The present invention has been made in view of such a circumstance, andit is an object of the present invention to provide a steering wheelwhich can be inexpensively manufactured, which can be downsized, whichis capable of easily mounting a module, and which has an appropriateoperability in operation of bringing a contact point of a horn deviceinto contact with something.

A steering wheel according to a fifth aspect of the present invention isprovided, and comprises: a steering wheel main body; a module; a pair ofhole portions which are provided so as to be spaced from each other ineither one of the steering wheel main body and the module; a pair ofhooks which are provided so as to be spaced from each other in anotherof the steering wheel main body and the module and which can berespectively inserted into the hole portions; a pair of engagementportions which are disposed in the respective hole portions, which arebiased in a predetermined direction crossing a insertion direction ofthe hooks into the hole portions, and which are engaged with the hooksthat are inserted into the hole portions so as to retain the hooks tothereby support the module with respect to the steering wheel main body;a locking portion which is provided between either of the pair of thehole portions and the pair of the hooks in either one of the steeringwheel main body and the module; a locking receiving portion which isprovided in another of the steering wheel main body and the module andwhich is adapted to engagingly lock the locking portion in the insertiondirection of the hooks into the hole portions; and a horn device whichcomprises: one contact point which is provided at least either one ofthe steering wheel main body and the module at a position of the lockingportion; and another contact point which is provided so as to be opposedto the one contact point in another of the steering wheel main body andthe module, the horn device being blown by way of contact of the one andanother contact points due to a relative movement of the module withrespect to the steering wheel main body along the insertion direction ofthe hooks into the hole portion.

A steering wheel according to a sixth aspect of the present invention isprovided in such a manner that the pair of hole portions are positionedat both of the left and right side parts in either one of the steeringwheel main body and the module, the pair of hooks are provided at aposition which corresponds to the pair of hole portions in another ofthe steering wheel main body main body and the module, the lockingportion is positioned at a central lower part in a transverse directionof either one of the steering wheel main body and the module, and thelocking receiving portion is provided at a position which corresponds tothe locking portion in another of the steering wheel main body and themodule.

With the steering wheel according to the fifth aspect of the presentinvention, the hole portions and the hooks are paired, and the module isfurther engagingly locked with the steering wheel main body by way ofthe locking portion and the locking receiving portion that arerespectively positioned between the pair of hole portions and the hooks;and therefore, the number of parts of the engagement members that aredisposed in the hole portions can be reduced, inexpensive manufacturingcan be carried out, and downsizing becomes possible in comparison withthe case of setting three or more hole portions and hooks, for example,while reliably engagingly locking the module with respect to thesteering wheel main body. In addition, the module can be mounted bymerely engagingly locking the locking portion with the locking receivingportion and then inserting the hooks into the hole portions; andtherefore, the module can be easily mounted. Further, one contact pointand another contact point are provided in correspondence with apositional relationship between the locking portion and the lockingreceiving portions; and therefore, the operability in operation ofbringing a contact point of the horn device into contact with somethingis improved.

With the steering wheel according to the sixth aspect of the presentinvention, the pair of hole portions and the pair of hooks are disposedboth of the left and right side parts, and the locking portion and thenlocking receiving portion are disposed at the central lower part in thetransverse direction. In this manner, the module can be engaginglylocked with the steering wheel main body in a well-balanced manner andreliably, and the operability in operation of bringing the contact pointof the horn device into something can be improved more remarkably.

In FIG. 14 and FIG. 15, reference numeral 10 a designates a steeringwheel, and the steering wheel 10 a is composed of: a module 11 a whichis disposed in front of an occupant at a driver's seat of a motorvehicle; a steering wheel main body 12 a serving as a steering wheelmain body in which the module 11 a is attached to the occupant's side; acover body (a body cover) 13 a serving a steering covering member whichis mounted on a counter-occupant side of the steering wheel main body 12a; and a finisher (a garnish) 14 a serving as a decoration member whichis mounted on the occupant's side of the steering wheel main body 12 a.

It is to be noted that the steering wheel 10 a is generally mounted to asteering shaft serving as a steering device, although not shown, whichis provided in a state in which the device is inclined in a inclinedstate with respect to a horizontal direction (a perpendiculardirection); and however, hereinafter, a description will be given on theassumption that: the side of the module 11 a is defined as theoccupant's side, a front side, or a rear side; the steering wheel sideis defined as a vehicle body side, a rear side, or a front side; aforward and backward direction taken along the steering shaft is definedas an axial side; and directions such as the forward and backwarddirection and a vertical direction are defined with reference to aforward direction of a vehicle body provided with the steering wheel 10a.

In the embodiment, the module 11 a is obtained as an airbag device (anairbag module) provided with: a case 24 a provided with a base plate 21a which is a mounting member serving as a housing body and an airbagcover 22 a serving as a covering body, the case being adapted to house afolded airbag 23 a; an inflator 25 a which is disposed in the case 24 a;and a retainer 26 a or the like.

The base plate 21 a shown in FIG. 10 (a) and FIG. 11 to FIG. 14 is alsoreferred to as a back plate or a back holder or the like; the base plateis compatible with a horn plate of a horn mechanism, although not shown;and the base plate is integrally injection-molded with a syntheticresin, for example. In addition, the base plate 21 a is provided with: aboard portion 31 a which is a mounting surface portion serving as a casemain body; and a peripheral wall portion 32 a which is erected on afront side all over the peripheral edge part on a surface side of theboard portion 31 a.

In the board portion 31 a, inflator mounting holes 34 a each formed inthe shape of a circular hole are opened in a substantially center part,and four mounting holes 35 a are respectively opened so as to surroundthe inflator mounting holes 34 a. Also, in the board portion 31 a, apair of columnar (cylindrical) hooks 37 a adapted to retractably mountthe module 11 a to a steering wheel main body 12 a are protrusivelyprovided on a rear side. In addition, in the board portion 31 a, thelocking portion 38 a adapted to retractably mount the module 11 a to thesteering wheel main body 12 a is protrusively provided on a rear side.Further, to the board portion 31 a, an electrically conductive platewhich is electrically conductive, although not shown, which is adaptedto set the movable contact point 39 a which is one contact point to aproximal end part of the locking portion 38 a, for example, isintegrally molded, is embedded, and is mounted.

The hooks 37 a are adapted to removably engagingly lock the module 11 aand the steering wheel main body 12 a and to guide the module 11 a alongthe front face to rear face direction with respect to the steering wheelmain body 12 a. In these hooks 37 a, at tip end sides, recessed portions41 which are narrowed hook portions are provided, and faces at tip endsides of the recessed portions 41 a are obtained as engagingly lockingfaces 42 a (FIG. 13b )). Also, tip end parts of the hooks 37 a each areformed in a conical shape so as to gradually narrow (to be reduced indiameter) to a respective one of the tip end sides. Also, in these hooks37 a, tip end sides are inserted into opening portions 44 a serving ashole portions of the steering wheel main body 12 a which will bedescribed later, the tip end sides are elastically engagingly locked andretained at positions of engagingly locking faces 42 a (recessedportions 41 a) by way of wires 45 a serving as engagement members whichare respectively mounted to these opening portions 44 a, and the tip endsides are movable along the front face to rear face direction withrespect to the opening portions 44 a (FIG. 13 (b)). In the embodiment,the hooks 37 a are positioned so as to be spaced from each other at bothof the left and right side parts at an upper part of base plate 21 a (aboard portion 31 a) of the module 11 a, that is, in a 9 o'clockdirection and a 3 o'clock direction in the steering wheel 10 a in itsneutral state. In addition, at the periphery of the proximal end side ofa respective one of the hooks 37 a, one end part (a rear end part) of ahorn spring 46 a which is a coil spring serving as biasing means forbiasing the module 11 a toward a rear side (the occupant's side) withrespect to the steering wheel 12 a is retained.

The locking portions 38 a are engagingly locked with the lockingreceiving portions 47 a that are provided on the side of the steeringwheel 12 a which will be described later; the locking portionsengagingly lock in the front face to rear face direction that is thedirection of insertion the hooks 37 a into the opening portions 44 aengagingly lock, specifically snap-fit in the front face direction; thelocking portions restrain a backlash with respect to the steering wheelmain body 12 a of the module 11 a, and operate the module 11 a so as toimprove operability when operating a horn device. The locking portions38 a each are provided with: a pair of protrusion portions 38 aa, 38 aaserving as restraining portions which protrude along a directionparallel to (substantially parallel to) the hooks 37 a and whichrestrain the position in the transverse direction of the lockingreceiving portions 47 a; and engagingly locking target portions 38 bawhich are directly engagingly locked with the locking receiving portions47 a while coupling the tip end parts of these protrusion portions 38aa, 38 aa to each other; and are formed in the shape of a loop (aU-shape) with respect to the board portion 31 a. Also, the lockingportions 38 a each are positioned at the central lower part in thetransverse direction of the base plate 21 a (the board portion 31 a) ofthe module 11 a, that is, in the 6 o'clock direction in the steeringwheel 10 in its neutral state. Therefore, the locking portions 38 a eachare positioned in the transverse direction between the hooks 37 a, 37 a,and are disposed at apex positions of a virtual isosceles triangle whenseen from a front side together with these hooks 37 a, 37 a. In otherwords, these hooks 37 a and locking portions 38 a are disposed so as tobe substantially transversely symmetrical to each other as a while.

The movable contact points 39 a are opposed to the fixed contact points48 a which are another contact points of a horn device which is disposedon the side of the steering wheel main body 12 a which will be describedlater, and constitute horn switches which are switches of the horndevice together with these fixed contact points 48 a. At these movablecontact points 39 a, there are set: a pair of upper movable contactpoints 39 aa, 39 aa which are a one of movable contact points disposedat both of the upper left and right side parts; and a lower movablecontact point 39 ba which is another movable contact point disposed at acentral lower part in the transverse direction. That is, the movablecontact points 39 a are respectively at both of the side parts and thelower part of the board portion 31 a of the base plate 21 a, and aredisposed at the apex positions of the virtual isosceles triangle whenseen from the front side.

The upper movable contact points 39 aa, 39 aa, at upper positions thanthose of the hooks 37 a, 37 a, are disposed at positions, a respectiveone of which is more proximal to the center in the transverse directionthan the center axes of these hooks 37 a, 37 a. Also, these uppermovable contact points 39 aa, 39 aa are positioned on the board portion31 a, that is, in proximity to an outer edge part of the base plate 21a.

The lower movable contact point 39 ba is disposed at a position which isslightly spaced upper than those of the locking portions 38 a incorrespondence with the positions of the locking portions 38 a.

The peripheral wall portion 32 a is adapted to surround the airbag 23 ain its folded state, and is positioned in a direction taken along theprotrusion direction of the airbag 23 a. Also, at the outside of theperipheral wall portion 32 a, a plurality of engagement portions 51 afor engaging and retaining the airbag cover 22 a are provided all overthe board portion 31 a. Although, in the embodiment, the engagementportions 51 a are opened, these engagement portions each may be formedin the shape of a hook or may be formed in the shape of a hook and in anopened state.

On the other hand, the airbag cover 22 a shown in FIG. 14 or the like isintegrally formed of a synthetic resin having its insulation property,and is provided with: a top plate portion 53 a serving as a cover mainbody adapted to cover a front side of a part of the steering wheel 10 a;and a mounting plate portion 54 a serving as a mounting wall portionwhich is provided so as to be protrusive to a lower side in arectangular cylinder shape from a front side which is a rear side of thetop plate portion 53 a.

On a front face which is the rear face of the top plate 53 a, at aposition which is surrounded by the mounting plate portion 54 a, a tearline which is a tear-off target portion, although not shown, the tearline being formed in a small groove shape in thickness dimension, isformed in a substantial H-shape in a planar view, and at the time ofinflation of the airbag, the airbag is configured to cleave and expandalong the tear line by way of an expansion pressure of the airbag.

The mounting plate portion 54 a is positioned outside of the peripheralwall portion 32 a of the base plate 21 a, and is formed along anexternal shape of the peripheral wall portion 32 a. Further, at themounting plate portion 54 a, engagingly locking protrusions, althoughnot shown, which are adapted to engage with the engagement portions 51 aof the base plate 21, are respectively provided.

The airbag 23 a is formed in a flat bag shape by single or a pluralityof base cloths, for example, and as is the case with the board portion31 a of the base plate 21 a, an inflator mounting hole 56 a formed inthe shape of a circular hole and four mounting holes 57 a which areprovided so as to surround the inflator mounting hole 56 a are formed.

The inflator 25 a is provided with: a disk-shaped inflator main bodyportion 61 a; and a flange portion 62 a which is provided so as to beprotrusive from the inflator main body portion 61 a to the outercircumferential side. In addition, in the inflator main body portion 61a, a gas injection nozzle, although not shown, is provided, and in theflange portion 62 a, four mounting holes 64 a are provided. Further, ata bottom part of the inflator main body portion 61 a, a contact point,although not shown, is provided. To the contact point, a wire harness isconnected via a connector, although not shown, and via the wire harness,the inflator 25 a is electrically connected to a control device.

The retainer 26 a is formed in the shape of a ring, and is providedwith: a retainer base portion 66 a which is formed of a metal plate orthe like; and four mounting bolts 67 a which are fixed to the retainerbase portion 66 a. Also, in the retainer base portion 66 a, an inflatormounting hole 68 a formed in the shape of a circular hole is shaped at acenter part. In addition, the mounting bolts 67 a are protrusivelyprovided on a rear side so as to surround the inflator mounting hole 68a, and appropriate nuts, although not shown, are respectively screwed.

Also, the retainer 26 a is inserted into the airbag 23 a, and the airbag23 a is folded in a predetermined state in a state in which the mountingbolts 67 a of the retainer 26 a are pulled out from the mounting holes57 a. Further, the folded airbag 23 a is covered with the airbag cover22 a, and an engagingly locking protrusion of the mounting plate portion54 a of the airbag cover 22 a is pushed against the side of the baseplate 21 a while the protrusion is positioned at the engagement portion51 a of the peripheral wall portion 32 a of the base plate 21 a with themounting bolts 67 a of the retainer 26 a being inserted into themounting holes 35 a. In this manner, the engagingly locking protrusionis inserted into and then engagingly locked with the engagement portion51 a and then the airbag cover 22 a and the base plate 21 a are fixed toeach other with just one touch of a finger (snap-in).

Further, while the mounting bolts 67 a that protrude to the rear side ofthe base plate 21 a is inserted into the mounting holes 64 a, theinflator 25 a is combined from the rear side of the base plate 21 a, andappropriate nuts are screwed and tightened with the mounting bolts 67 a.In this state, a portion on the front side of the inflator main bodyportion 61 a in which the gas injection nozzle of the inflator 25 a hasbeen provided is inserted into the airbag 23 a through the inflatormounting hole 34 a, and the module 11 a is constructed.

On the other hand, the steering wheel main body 12 a shown in FIG. 14and FIG. 15 is composed of: a rim portion (a ring portion) 71 a which isformed in the shape of a circular ring; a boss portion (a mountingportion) 72 a which is positioned inside of the rim portion 71 a; and aplurality of, in the embodiment, three spoke portions 73 a adapted tocouple these rim portion 71 a and boss portion 72 a to each other.

Also, the steering wheel main body 12 a is provided with: a metal-basedcored bar 75 a; and a soft covering portion 76 a adapted to integrallycover a part of the cored bar 75 a, and a rear side of the cored bar 75a is covered with the cover body 13.

The cored bar 75 a corresponds to the rim portion 71 a, the boss portion72 a, and two spoke portions 73 a; the cored bar is provided with: a rimcored bar 81 a; a boss cored bar 82 a serving as a supporting portion;and spoke cored bars 83 a serving as coupling portions; and the coredbar is formed so as to be substantially transversely symmetrical to eachother as a whole. It is to be noted that a remaining spoke portion 73 ais composed of a finisher 14 a, for example.

The boss cored bar 82 a is also referred to as a boss plate or a hubcore or the like, and integrally has, at a center part, a cylindricalboss 85 a which is engagingly fitted to a steering shaft. Also, in theboss cored bar 82 a, the opening portions 44 a and the fixed contactpoints 48 a that constitute a horn switch device are respectivelyprovided. Further, at a lower part of the boss cored bar 82 a, there areprotrusively provided protrusion receptacle portions 86 a in which thelocking receptacle portions 47 a are provided. The protrusion receptacleportions 86 a each have: arm portions 86 aa, 86 aa extending to a lowerside from both sides at a lower part of the boss cored bar 82 a; and asupporting portion 86 ba which is adapted to couple these arm portions86 aa, 86 aa in the transverse direction and in which the lockingreceiving portions 47 a and the fixed contact points 48 a are disposed.

The opening portions 44 a are provided so as to pass through the bosscored bar 82 a in a forward and backward direction which is a thicknessdirection, at positions which correspond to the hooks 37 a, that is, atpositions which are spaced at both of the left and right sides at anupper part of the boss cored bar 82 a (at positions which is proximal toa proximal end of the spoke cord bar 83 a). These opening portions 44 aeach are formed in the shape of a circular hole. Also, tip end sides ofthe hooks 37 a are respectively inserted into these opening portions 44a.

A respective one of the wires 45 a is also referred to as a “one touch”wire, and is formed of a wire rod (a piano wire) such as an elasticallydeformable metal. In the embodiment, the respective one of the wires 45a is provided with: a wire main body 91 a which is a twisted coil springand which serves as an engagement member main body wounded in a coilshape; a first arm 92 a extending from the wire main body 91 a in alinear shape along a tangential direction; and a second arm 93 aextending from the wire main body 91 a in a linear shape along thetangential direction forming an obtuse angle with respect to the firstarm 92 a; and further, at a tip end side of the first arm 92 a, thereare integrally provided: bent (V-shaped) locking portions 94 a adaptedto engage with recessed portions 71 a of the hooks 37 a of the module 11a so as to engagingly lock the hooks 37 a; and an operating portions 95for removing operation which is continuous between these lockingportions 94 a (FIG. 13 (a)). The respective one of the wires 45 achanges an angle between the first arm 92 a and the second arm 93 a froma natural state (a no-load state) to thereby produce a biasing load soas to restore the angle between the first arm 92 a and the second arm 93a to the natural state by way of the wire main body 91 a.

Also, in the respective one of the wires 45 a, the wire main body 91 ais retained by a first retaining portion 97 a formed in the shape of acircular hole, the first retaining portion being provided so as to passthrough the boss cored bar 82 a in the front face to rear facedirection, the first arm 92 a is retained by a second retaining portion98 a which is protrusively provided on a front side of the boss coredbar 82 a, and at a position of the operating portion 95 a, the secondarm 93 a is hooked and retained in a state in which the second arm isexposed to a hooking retaining portion 99 a which is opened in an arcshape with respect to the boss cored bar 82 a and then the lockingportions 94 a are respectively exposed from the opening portions 44 a.

At the positions that correspond to the locking portions 38 a, that is,at the central lower parts in the transverse direction of the boss coredbar 82 a, the locking receiving portions 47 a each are provided so as tobe protrusive in the shape of a claw from the boss cored bar 82 a (arespective one of the protrusive receptacle portions 86 a) to a lowerside; the locking receiving portions engagingly lock the lockingportions 38 a in the front face to back face direction which is thedirection of insertion of the hooks 37 a into the opening portions 44 a,and specifically, snap-fit them in the front face direction.

The fixed contact points 48 a are formed of a member such as a metalhaving its electrical conductivity, and are disposed so as to be opposedto the movable contact points 39 a on the side of the module 11 a. Thatis, at the fixed contact points 48 a, there are set: a one of upperfixed contact points 48 aa, 48 aa which are a pair of fixed contactpoints disposed at both of the left and right side parts at the upperpart of the boss cored bar 82 a and opposed to the upper movable contactpoints 39 aa, 39 aa; and a lower fixed point 48 ba which is anotherfixed contact point disposed directly at the central lower part in thetransverse direction, that is, above the locking receiving portion 47 aof the protrusion receptacle portion 86 a (the supporting portion 86 ba)and opposed to the lower movable contact point 39 ba. Therefore, thefixed contact points 48 a are respectively disposed at both side partsand the lower part of the board portion 31 a of the base plate 21 a, andare disposed at apex positions of a virtual isosceles triangle when seenfrom a front side.

In so far as the steering wheel main body 12 a is concerned, the coverbody 13 a is mounted to the steering wheel main body 12 a while thecover body is combined and positioned from a rear side. After that, theboss 85 a of the steering wheel main body 12 a is engagingly fitted tothe steering shaft and then is tightened and fixed with appropriatenuts, although not shown.

In so far as the steering wheel main body 12 a is concerned, while themodule 11 a hooks the locking receiving portions 47 a on the lockingportions 38 a (the engagingly locking target portions 38 ba), therespective opening portions 44 a and the respective hooks 37 a arepositioned and are pushed against each other from the front side. Inthis manner, the locking portionlocking portions 94 a of the wires 45 athat are positioned in the respective opening portions 44 a engage withthe engagingly locking faces 4 a of the recessed portions 41 a of thehooks 37 a (FIG. 13b ). As a result, the module 11 a engages with thesteering wheel main body 12 a at three portions, both sides and thelower side; and the module is snap-fitted and supported.

As a result, the module 11 a is positionally restrained in a respectiveone of the forward and backward direction, the vertical direction; thetransverse direction relative to the steering wheel main body 12 a, therespective hooks 37 a are snap-fitted in the front face direction by wayof the wires 45 a; and the locking portions 38 a are snap-fitted in thefront face direction by way of the locking receiving portions 47 a.

In addition, in this state, the steering wheel main body 12 a is guidedalong the front face to back face direction by way of the respectivehooks 37 a.

Also, for example, electrical wiring is provided for contact points ofthe inflator 25 a, whereby the steering wheel 10 a that is provided withthe module 11 a is constructed in a state in which the steering wheel ismounted to the steering shaft.

In so far as the thus constructed steering wheel 10 a is concerned,operation at the time of cruising is carried out by the occupant at thedriver's seat gripping and turning the rim portion 71 a. In addition,the occupant pushes and operates the airbag cover 22 a of the module 11a that is compatible with a pushing operation portion against thebiasing loads of the respective horn springs 46 a. In this manner, themodule 11 a is relatively guided to the front side (FIG. 13 (b) and FIG.13 (c) by way of engagement between the respective hooks 37 a and therespective opening portions 44 a and by way of engagement between thelocking portions 38 a and the locking receiving portions 47 a, and whenany movable contact point 39 a comes into contact with a fixed contactpoint 48 a, the horn device on the vehicle body side is blown.

Also, when the module 11 a is removed from the steering wheel main body12 a, a tool provided with a L-shape, for example, although not shown,is inserted into the operating portion 95 a that is exposed from thehooking retaining portion 99 a, the module is pulled in a directionwhich is opposite to that of the hook 37 a, and the module is releasedfrom the recessed portions 41 a. In this manner, the module isdisengaged from the hooks 37 a by way of the wires 45 a, and the module11 a can be removed.

On the other hand, in case of a front face collision of a motor vehicle,a gas is rapidly injected from the inflator 25 a into the airbag 23 aand then the folded housed airbag 23 a rapidly inflates. Then, by way ofthe inflation pressure of the airbag 23 a, the airbag cover 22 a cleavesalong the tear line and then the protrusion opening of the airbag 23 ais formed, and the airbag 23 a protrudes from this protrusion openingand then inflates and expands in front of the occupant to therebyconstrain and protect the occupant. At this time, from the protrusionopening, the module 11 a is retained by the steering wheel main body 12a against the impact at the time of inflation and expansion of theairbag 23 a because the respective hooks 37 a are mainly engaginglylocked by way of the respective wires 45 a.

Thus, according to the fourth embodiment, the openings 44 a and thehooks 37 a are paired, and the module 11 a is further engagingly lockedwith the steering wheel main body 12 a by way of the locking portions 38a and the locking receiving portions 48 a that are positioned betweenthe pair of opening portions 44 a, 44 a and hooks 37 a, 37 a; andtherefore, the number of parts of the wires 45 a that are disposed inthe opening portions 44 a can be reduced, the assembling workload of thewires 45 a can be restrained, and downsizing becomes possible incomparison with the case of setting three or more pairs of openingportions and hooks, for example, while engagingly locking the module 11a with the steering wheel main body 12 a. In addition, the lockingportions 38 can be mounted merely by engagingly locking them with thelocking receiving portions 47 a and then inserting the hooks 37 a, 37 ainto the opening portions 44 a, 44 a; and therefore, the module 11 a canbe easily mounted. Further, the contact points 39 a, 48 a are providedin correspondence with a positional relationship between the lockingportions 38 and the locking receiving portions 47 a; and therefore, theoperability in operation of bringing the contact points 39 a, 48 a ofthe horn device into contact with something is improved.

Furthermore, a pair of opening portions 44 a, 44 a and a pair of hooks37 a, 37 a are disposed at both of the left and right side parts, andthe locking portions 38 a and the locking receiving portions 47 a aredisposed at the central lower part in the transverse direction. In thismanner, the module 1 a can be engagingly locked in a well-balancedmanner and reliably with the steering wheel main body 12 a, and at thetime of a pushing operation of bringing the contact points 39 a, 48 a ofthe horn device into contact with something, a backlash of the module 11a is restrained, smooth operation is carried out, and its relatedoperability can be improved more remarkably.

It is to be note that while, in the fourth embodiment described above,there has been employed a construction in which the hooks 37 a areprotrusively provided in the module 11 a (the base plate 21 a), and theopening portions 44 a and the wires 45 a are disposed in the steeringwheel main body 12 a (the boss cored bar 82 a), there can also employeda construction in which the opening portions 44 a and the wires 45 a aredisposed in the module 11 a (the base plate 21 a), and the hooks 37 aare protrusively provided in the steering wheel main body 12 a (the bosscored bar 82 a).

Still furthermore, as the module 11 a, there can be employed a pad bodyadapted to house a shock absorbing body, for example, the airbag device.

INDUSTRIAL APPLICABILITY

The present invention can be preferably employed as an airbag device fordriver's seat of a motor vehicle, for example.

1-5. (canceled)
 6. A steering wheel comprising: a steering wheel mainbody; a module; a plurality of hole portions which are provided ateither one of the steering wheel main body and the module; a pluralityof hooks which are provided at another of the steering wheel main bodyand the module and which can be respectively inserted into the holeportions; and a plurality of engagement members which are disposed atthe respective hole portions, which are biased in a predetermineddirection crossing an insertion direction of the hooks into the holeportions, and which are engaged with the hooks that are inserted intothe hole portions so as to retain the hooks to thereby support themodule on the steering wheel, wherein the hook that is one of theplurality of hooks comprises: a positioning reference portion which isprotrusively provided on an outside face and which comes into contactwith an inside face of one of the hole portions so as to restrain aposition of one of the hooks at the one hole portion; and a plurality ofadjustment portions which is protrusively provided on an outside face ata position different from the positioning reference portion and whichelastically comes into contact with the inside face of the one holeportion by the positioning reference portion coming into contact withthe inside face of one of the hole portions.
 7. The steering wheelaccording to claim 1, wherein a sum of biasing loads with respect to theplurality of hooks of the plurality of engagement members issubstantially
 0. 8. The steering wheel according to claim 1, whereinother remaining hooks except one of the plurality of hooks comprise aplurality of adjustment portions which are protrusively provided on theoutside face and which elastically come into contact with the insidefaces of other remaining hole portions by the positioning referenceportion of one of the hooks coming into contact with the inside face ofone hole portion.
 9. The steering wheel according to claim 1, furthercomprising: a locking portion which is provided between either of thepair of the hole portions and the pair of the hooks in either one of thesteering wheel main body and the module; a locking receiving portionwhich is provided in another of the steering wheel main body and themodule and which is adapted to engagingly lock the locking portion inthe insertion direction of the hooks into the hole portions.